How to tell if someone is stealing your Wi-Fi — and what you can do about it

Everyone and their granny has a Wi-Fi connection in their home, but not all of them run as fast as you might like. While that might just mean you need a new router, it’s possible someone is thieving your connection too. Fortunately, there are ways to detect it and block them from accessing it ever again.

As long as you have your MAC address and an app or two, you can determine if someone is stealing your Wi-Fi or if your connection is just slow. Here’s how.

Is someone stealing your Wi-Fi?

If you only have a few Wi-Fi devices in your house, you may want to unplug or turn them all off, and then watch the wireless signal light on your router. If the light continues to flicker, someone else is using your Wi-Fi.

However, this method only works if you can be sure that every wireless-capable device you have is powered down, which may not be easy to do in many homes. So, we present two in-depth methods for checking for Wi-Fi thieves, no matter what setup you have. If you need a refresher on wireless networking itself, then check out our Wi-Fi overview.

Method 1: Use an app

A number of apps are available to provide automatic searches for unusual devices logged into your Wi-Fi network. Checking those devices, especially if they’re connecting at odd times of day when no friends are over, can provide valuable clues. Here are a few apps that can help you pinpoint problems.

Wi-Fi Thief Detector: This app is easy to download and designed to produce fast results. It will show you how many devices are on your router, help you spot devices that don’t belong there, and connect you with your router settings so you can quickly make the changes you need to protect your router (see below for more information).

Paessler PRTG Network Monitor: Paessler’s solution is a full suite of router management tools, including automatic detection of strange traffic, analysis of how the network is being used, and other in-depth tools. It may be a bit much for the average worried homeowner, but it’s an excellent tool for small businesses concerned about someone hopping on their network without permission. We suggest you stick with the 30-day free trial, which should be enough to root out any problems.

F-Secure Router Checker: F-Secure is a web-based tool that is useful if you want to avoid any downloads. This tool checks for more serious hacking — specifically, it looks for signs that someone is using stealthy setting tweaks to hijack your internet, which may be useful for tougher cases.

Wireless Network Watcher: This independent software is designed to help Windows and MacOS users watch for suspicious wireless activity and monitor all currently connected devices.

Fing: Fing is an iOS download for more mobile-oriented protection. It allows you to immediately see connected devices, what type of devices they are, and the nature of their connection, MAC address, and so on. You can also check Wi-Fi connection behavior to note particularly busy times that could indicate someone else is hopping onto your network.

Method 2: Check administrator logs

If you suspect that someone is stealing your Wi-Fi, you need to log in to your router’s administration page. Most people can do this by typing 192.168.1.1 or 192.168.2.1 into the address bar. If these don’t work, swing on over to our guide for accessing your router’s admin panel.

Once you’ve accessed the admin page, you’ll need to locate the page listing the various Media Access Control (MAC) addresses connected to your computer. The location of this page will differ depending on your router, but you may find it under wireless configuration, wireless status, or in the DHCP client list. You can use this list to count how many devices are connected to your internet. If you see six MAC addresses — any device connected to your network will have its own unique MAC address — but only have four devices in your home, somebody is probably stealing your internet.

Note: Old phones, gaming consoles, Wi-Fi-enabled cameras, and other connected devices may show up on the MAC address list. You can get a better handle on which MAC address represents which device by using a website like macvendors.com.

How to keep outsiders away

123RF

If you suspect someone is stealing your Wi-Fi, it’s a good idea to beef up security (penalties for Wi-Fi theft vary greatly, so consult local law enforcement for follow-up). If you don’t have a password on your network, add one. If you still use the default router name and password, change it — you can do this from the admin page on your router.

To change your password, look for the pre-shared key in your security settings. Changing your wireless password will kick off all current devices (including those unwanted freeloaders), so you’ll have to reconnect your devices once you have a new password.

To change your router name, locate the Service Set Identifier. This is typically found in the wireless settings menu. Look up more specific instructions for your specific brand of router if necessary.

Lastly, it’s important to use the strongest wireless network encryption available for consumers. At this time, though WPA2 may be the most commonly used, WPA3 is the strongest. So you may want to start thinking about getting a new one that features WPA3.

If you have an out of date router that’s no longer supported and you don’t have access to security features like these, then it’s time to start thinking about getting a new router.

Remove strangers on your Wi-Fi

Sure, this is all great, but what do you do if you find strangers on your Wi-Fi and want to get rid of them? The easiest and fastest method is to simply change your password to something longer and more robust. This will kick all devices off the network, allowing you to sign back in and blocking people without the password. For casual moochers, this will be enough to deter further efforts, although you should still keep an eye on connected devices to make sure.

Otherwise, you can also look for an option on your router administration page that says MAC filtering, Device filtering, or something similar. This allows you to add MAC numbers to a list of blocked devices that your router won’t allow. Pick out the strange MAC numbers from unfamiliar devices, and add them to this list. Today’s router apps, like with Google Home, make it particularly easy to pick a device on your network and block it with little effort. This isn’t absolutely foolproof, as MAC addresses can be spoofed, but that would be pretty rare in situations like this.

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